The Industrial Revolution was important for America's economic development from 1820-1870, spreading from Britain initially. Technology like railroads drove industrialism by increasing efficiency and communication. This created wealth and demand for more technology, which became essential to the US economy. Industrialism attracted rural Americans and immigrants to cities, shifting the US from agrarian to urban. Immigration provided cheap labor that was important for industrialism's success. Early US factories used horse or water power, limiting industrialization to areas like New England with fast rivers until better technology developed.